Flame retardants in US products are changing rapidly primarily because the most common flame retardants, polybrominated diphenyl ethers (PBDEs), were phased out from 2004 to 2013 because of reported evidence of liver and thyroid effects, developmental changes and neurotoxicity. Many consumer products which previously used PBDEs now use alternative flame retardants. Occupational exposure to these alternative flame retardants is not currently well characterized. This project has evaluated exposure to nine alternative flame retardants plus a panel of PBDEs. Exposure has been assessed among workers involved in the manufacture, installation or use of goods containing these nine alternative flame retardants. Worksite categories included in the study were: manufacture of products that use flexible polyurethane foams, plastics, or resins, fabrication and manufacture of rigid polystyrene foam, cutting, installing or spraying polyurethane foam insulation at construction sites, gymnasiums, manufacture of wire harnesses or printed circuit boards, and fire service. Site visits have optimized sampling methods to assess exposure to dominant flame retardants used in each worksite category. During FY18, all remaining sites were evaluated for a total of 19 workplaces. Each workplace received a summary report of their company exposure results. Additionally, all workers (n=105) who participated in the study received their individual results. A database that includes exposures for all companies was completed. The first manuscript on Spray Polyurethane Foam workers has been prepared and submitted for publication.